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Re: [ft] Clipping Of Empty Glyphs (space)
From: |
Werner LEMBERG |
Subject: |
Re: [ft] Clipping Of Empty Glyphs (space) |
Date: |
Wed, 04 Jun 2008 14:59:08 +0200 (CEST) |
> Is there a real reason for me to use Get_CBox, then?
Yes.
> I'd like (if it's possible) to treat "real" glyphs and "empty"
> glyphs in a uniform manner.
You can't. An empty glyph never has something to draw, but it still
has dimensions. It's a natural non-uniformity.
> Should I not simply switch my "engine" to never use CBox, and
> instead go with glyph metris (bearing, advance, width, height) and
> pen position?
Metrics don't reliably reflect the real dimensions of a glyph. Just
think of a `O' character -- there's some overshoot below and above the
glyph which is not part of the bounding box given by the metrics.
> Do empty characters still have an actual width and bearing? Or do I
> have to rely on glyph advance in such special cases?
Empty glyphs in general don't have a width or a bearing. You should
use the advance width for that.
Note that, for example, TeX fonts don't have a space glyph at all
because it is something redundant in general -- in most cases it's the
job of the text formatting engine to adjust the spaces between words
while breaking text into paragraphs.
Werner